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/*
* Copyright (C) 2014 Igalia S.L. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
* THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "config.h"
#include "CryptoAlgorithmAES_CBC.h"
#if ENABLE(WEB_CRYPTO)
#include "CryptoAlgorithmAesCbcCfbParams.h"
#include "CryptoKeyAES.h"
#include "NotImplemented.h"
#include <pal/crypto/gcrypt/Handle.h>
#include <pal/crypto/gcrypt/Utilities.h>
namespace WebCore {
static Optional<Vector<uint8_t>> gcryptEncrypt(const Vector<uint8_t>& key, const Vector<uint8_t>& iv, Vector<uint8_t>&& plainText)
{
// Determine the AES algorithm for the given key size.
auto algorithm = PAL::GCrypt::aesAlgorithmForKeySize(key.size() * 8);
if (!algorithm)
return WTF::nullopt;
// Create a new GCrypt cipher object for the AES algorithm and the CBC cipher mode.
PAL::GCrypt::Handle<gcry_cipher_hd_t> handle;
gcry_error_t error = gcry_cipher_open(&handle, *algorithm, GCRY_CIPHER_MODE_CBC, 0);
if (error != GPG_ERR_NO_ERROR) {
PAL::GCrypt::logError(error);
return WTF::nullopt;
}
// Use the given key for this cipher object.
error = gcry_cipher_setkey(handle, key.data(), key.size());
if (error != GPG_ERR_NO_ERROR) {
PAL::GCrypt::logError(error);
return WTF::nullopt;
}
// Use the given IV for this cipher object.
error = gcry_cipher_setiv(handle, iv.data(), iv.size());
if (error != GPG_ERR_NO_ERROR) {
PAL::GCrypt::logError(error);
return WTF::nullopt;
}
// Use the PKCS#7 padding.
{
// Round up the size value to the next multiple of the cipher's block length to get the padded size.
size_t size = plainText.size();
size_t paddedSize = roundUpToMultipleOf(gcry_cipher_get_algo_blklen(*algorithm), size + 1);
// Padded size should be bigger than size, but bail if the value doesn't fit into a byte.
ASSERT(paddedSize > size);
if (paddedSize - size > 255)
return WTF::nullopt;
uint8_t paddingValue = paddedSize - size;
plainText.grow(paddedSize);
std::memset(plainText.data() + size, paddingValue, paddingValue);
}
// Finalize the cipher object before performing the encryption.
error = gcry_cipher_final(handle);
if (error != GPG_ERR_NO_ERROR) {
PAL::GCrypt::logError(error);
return WTF::nullopt;
}
// Perform the encryption and retrieve the encrypted output.
Vector<uint8_t> output(plainText.size());
error = gcry_cipher_encrypt(handle, output.data(), output.size(), plainText.data(), plainText.size());
if (error != GPG_ERR_NO_ERROR) {
PAL::GCrypt::logError(error);
return WTF::nullopt;
}
return output;
}
static Optional<Vector<uint8_t>> gcryptDecrypt(const Vector<uint8_t>& key, const Vector<uint8_t>& iv, const Vector<uint8_t>& cipherText)
{
// Determine the AES algorithm for the given key size.
auto algorithm = PAL::GCrypt::aesAlgorithmForKeySize(key.size() * 8);
if (!algorithm)
return WTF::nullopt;
// Create a new GCrypt cipher object for the AES algorithm and the CBC cipher mode.
PAL::GCrypt::Handle<gcry_cipher_hd_t> handle;
gcry_error_t error = gcry_cipher_open(&handle, *algorithm, GCRY_CIPHER_MODE_CBC, 0);
if (error != GPG_ERR_NO_ERROR) {
PAL::GCrypt::logError(error);
return WTF::nullopt;
}
// Use the given key for this cipher object.
error = gcry_cipher_setkey(handle, key.data(), key.size());
if (error != GPG_ERR_NO_ERROR) {
PAL::GCrypt::logError(error);
return WTF::nullopt;
}
// Use the given IV for this cipher object.
error = gcry_cipher_setiv(handle, iv.data(), iv.size());
if (error != GPG_ERR_NO_ERROR) {
PAL::GCrypt::logError(error);
return WTF::nullopt;
}
// Finalize the cipher object before performing the decryption.
error = gcry_cipher_final(handle);
if (error != GPG_ERR_NO_ERROR) {
PAL::GCrypt::logError(error);
return WTF::nullopt;
}
// Perform the decryption and retrieve the decrypted output.
Vector<uint8_t> output(cipherText.size());
error = gcry_cipher_decrypt(handle, output.data(), output.size(), cipherText.data(), cipherText.size());
if (error != GPG_ERR_NO_ERROR) {
PAL::GCrypt::logError(error);
return WTF::nullopt;
}
// Remove the PKCS#7 padding from the decrypted output.
{
// The padding value can be retrieved from the last byte.
uint8_t paddingValue = output.last();
if (paddingValue > gcry_cipher_get_algo_blklen(*algorithm))
return WTF::nullopt;
// Padding value mustn't be greater than the size of the padded output.
size_t size = output.size();
if (paddingValue > size)
return WTF::nullopt;
// Bail if the last `paddingValue` bytes don't have the value of `paddingValue`.
if (std::count(output.end() - paddingValue, output.end(), paddingValue) != paddingValue)
return WTF::nullopt;
// Shrink the output Vector object to drop the PKCS#7 padding.
output.shrink(size - paddingValue);
}
return output;
}
ExceptionOr<Vector<uint8_t>> CryptoAlgorithmAES_CBC::platformEncrypt(const CryptoAlgorithmAesCbcCfbParams& parameters, const CryptoKeyAES& key, const Vector<uint8_t>& plainText, Padding)
{
auto output = gcryptEncrypt(key.key(), parameters.ivVector(), Vector<uint8_t>(plainText));
if (!output)
return Exception { OperationError };
return WTFMove(*output);
}
ExceptionOr<Vector<uint8_t>> CryptoAlgorithmAES_CBC::platformDecrypt(const CryptoAlgorithmAesCbcCfbParams& parameters, const CryptoKeyAES& key, const Vector<uint8_t>& cipherText, Padding)
{
auto output = gcryptDecrypt(key.key(), parameters.ivVector(), cipherText);
if (!output)
return Exception { OperationError };
return WTFMove(*output);
}
} // namespace WebCore
#endif // ENABLE(WEB_CRYPTO)